Firefox Performance Portal

The frontend for performance.mozilla.org. Built with SvelteKit and Chart.js as a static site; data is fetched in the browser from Treeherder, Taskcluster, Bugzilla, and Redash.

Development

Use Node.js 22 or later.

npm ci
npm run dev          # http://localhost:5173

npm run format       # format source with Prettier
npm run lint         # check correctness with oxlint
npm run check        # check types and Svelte components
npm test             # unit and component tests
npm run test:e2e     # browser tests; builds and serves the site automatically

Install Chromium before the first browser test run: npx playwright install chromium. Browser tests stub upstream services in e2e/fixtures.ts.

Code layout

• src/routes/: dashboard pages and the shared layout.
• src/lib/<dashboard>/: dashboard configuration, data loading, and calculations.
• src/lib/components/: shared charts, tables, and controls.
• src/lib/api/: API clients and data parsers.
• queries/: SQL for the Redash data sources.

View state lives in URL query parameters. Controls use the dashboard's state helpers to change selected fields while preserving the rest. src/hooks.ts maps .html URLs onto routes, and src/lib/param-aliases.ts normalizes query parameter aliases.

Use resource() from src/lib/resource.svelte.ts for reactive async data. Read individual $derived fields synchronously in its callback, before any await, so unrelated URL changes do not trigger a fetch. Pass its abort signal to data loaders; results from cancelled runs are discarded. Shared cached JSON requests finish independently of any one caller's cancellation.

Tests live next to their subjects; browser tests live in e2e/.

Deployment

npm run build produces static files in build/. Use npm run preview to inspect the build locally. Routes support both /speedometer and /speedometer.html spellings; /index.html opens the home page.

The Pages workflow checks formatting, lint, types, unit tests, and the build on pull requests to main and pushes to main. Lint warnings fail the check; browser tests run locally. Successful builds on main deploy build/. In the repository's Pages settings, select GitHub Actions as the publishing source.

Leave BASE_PATH unset for deployment: the same build serves performance.mozilla.org/ and mozilla.github.io/performance/ using relative asset paths.